Deuteronomy 1:3

1:3 However, it was not until the first day of the eleventh month of the fortieth year that Moses addressed the Israelites just as the Lord had instructed him to do.

Deuteronomy 8:2

8:2 Remember the whole way by which he has brought you these forty years through the desert so that he might, by humbling you, test you to see if you have it within you to keep his commandments or not.